Golf club head

ABSTRACT

A golf club head includes: a face portion; a sole portion; a side portion; a crown portion defining a hollow portion with the face portion, the sole portion and the side portion; a hosel portion; an adhesive material provided on an inner surface of the hollow portion; and a protruding portion for dividing an arrangement area of the adhesive material, the protruding portion being provided on the sole portion.

BACKGROUND

1. Field of the Invention

The present invention relates to a hollow golf club head, particularly, to a golf club head provided with an adhesive material for attaching foreign matter therein.

2. Description of the Related Art

As a head of a wood type golf club such as a driver or a fairway wood, a hollow metallic golf club head is widely used. In general, a hollow wood type golf club head has a face portion for hitting a ball, a crown portion constituting an upper surface portion of the golf club head, a sole portion constituting a bottom surface portion of the golf club head, a side portion constituting side surface portions of a toe side, a back side and a heel side of the golf club head, and a hosel portion. A shaft is inserted into the hosel portion and is fixed to the golf club head by a bonding material or the like, thereby constituting the golf club head.

As a metal which forms the hollow golf club head, aluminum alloy, stainless steel or titanium alloy is used. Furthermore, a part of the golf club head is also formed of a fiber-reinforced synthetic resin.

When foreign matter including minute pieces of metal or the like is present in an inner part of the hollow golf club head, the foreign matter moves in the golf club head when the golf club moves and an abnormal sound such as wriggling or crunching is generated. As the foreign matter, casting sediments or the like of a metallic golf club head are included.

In JP-A-7-148288, there is a description in which foreign matter particles are attached and captured by providing an adhesive material layer within the golf club head. In JP-A-148288, the adhesive material layer is provided in an inner surface of the sole portion or the crown portion over a wide range.

When the adhesive material layer is attached to the inner portion of the hollow golf club head, a primary natural frequency of the golf club head is low when a ball is hit, and the frequency of the striking sound is decreased, so that a sound range of the striking sound becomes a low sound. Particularly, as in JP-A-7-148288, when the adhesive material layer is provided in the wide range of the sole portion, the primary natural frequency of the sole portion is decreased, and a high fresh striking sound called “snap” peculiar to the metal head is not generated. For that reason, a golf club user (a golfer) may wonder whether a shot was a miss shot or not even when performing a nice shot.

SUMMARY

An object of the present invention is to solve the above-mentioned problem and provide a golf club head which generates a fresh striking sound.

According to an aspect of the invention, there is provided a golf club head including: a face portion; a sole portion; a side portion; a crown portion defining a hollow portion with the face portion, the sole portion and the side portion; a hosel portion; an adhesive material provided on an inner surface of the hollow portion; and a protruding portion for dividing an arrangement area of the adhesive material, the protruding portion being provided on the sole portion.

The protruding portion may be separated from the face portion.

The protruding portion may be connected to a heel side of the face portion.

The hosel portion may communicate with an inside and an outside of the golf club head, and the arrangement area may be located at a lower side of the hosel portion.

The protruding portion may be located nearer a heel portion in relation to a middle of a toe and heel direction of the sole portion.

A golf club head of the present invention includes an adhesive material therein, and foreign matter is attached and collected to the adhesive material, so an abnormal sound due to movement of the foreign matter is prevented.

In the present invention, a protruding portion is provided on a sole portion to divide an arrangement area of the adhesive material, and the adhesive material is arranged in the arrangement area, so the adhesive material is present only in a limited range of the sole portion. For that reason, a decline in primary natural frequency of the sole portion during ball hitting due to the provision of the adhesive material is suppressed, whereby the striking sound having no level difference with a golf club head without the adhesive material is generated.

When the protruding portion is separated from the face portion, ball striking speed increases without affecting the flexure of the face portion during ball hitting. However, even when the protruding portion is connected to the heel side of the face portion, the ball striking speed increases while hardly affecting the flexure of the face portion during ball hitting.

In addition, in a case where the hosel portion has a through hole shape, there is a fear that the foreign matter attached to an inner surface of the hosel or a front end of the shaft may enter the golf club head when the shaft is inserted into the hosel portion. When the adhesive material arrangement area is set in an area of a lower part of the hosel portion, the foreign matter fallen down from the hosel portion falls down on the adhesive material as is and is collected, so an abnormal sound occurrence caused by the foreign matter is securely prevented. In addition, when the adhesive material in a heat melting state is injected from the hosel portion into the golf club head, the adhesive material is blocked by the protruding portion, so that the adhesive material is arranged further toward the adhesive material arrangement area of the heel side than the protruding portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawing which is given by way of illustration only, and thus is not limitative of the present invention and wherein:

FIG. 1 is a perspective view from a rear part and an upper part with a crown portion cut away which shows a golf club head relating to an embodiment;

FIG. 2 is a plane view with a crown portion cut away which shows a golf club head relating to an embodiment;

FIG. 3 is a sectional view along line III-III in FIG. 2 of the golf club head relating to an embodiment;

FIG. 4 is a perspective view from a rear part and an upper part with a crown portion cut away which shows a golf club head relating to another embodiment;

FIG. 5 is a plane view with a crown portion cut away which shows a golf club head relating to still another embodiment; and

FIG. 6 is a plane view with a crown portion cut away which shows a golf club head relating to another embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present embodiments will be described with reference to the drawings. FIGS. 1 to 3 show a golf club head according to a first embodiment. Furthermore, in order to clarify a configuration of a golf club head 1, an adhesive material is not shown in FIG. 1.

The golf club head 1 has a hollow shape, which includes a face portion 2, a crown portion 3, a sole portion 4, a side portion 5 and a hosel portion 6, and is formed integrally of a metal such as titanium alloy as a whole. As the metal, various materials such as titanium, titanium alloy, aluminum alloy, and stainless steel can be used. It is desirable that a volume of the golf club head be equal to or larger than 350 cc, for example, about 400 to 460 cc.

As shown in FIG. 3, the hosel portion 6 has a through hole shape. In order to make a lower part area of a lower end of the hosel portion 6 as an arrangement area of the adhesive material 7, a protruding portion 8 protrudes from the sole portion 4. In the present embodiment, the protruding portion 8 has a L shape in which a front portion 8 a and a rear portion 8 b intersect approximately in a perpendicular shape when seen in a plane. An intersecting portion of the front portion 8 a and the rear portion 8 b is the furthest away from the heel 1 h (near a toe 1 t) and approaches to the heel 1 h as it goes to the front end side and the rear end side.

The front end of the protruding portion 8 is slightly (e.g., 1 to 10 mm, particularly, 2 to 5 mm) separated from the face portion 2. Although the rear end of the protruding portion 8 extends to the side portion 5 of the heel 1 h side, the rear end may be slightly (e.g., about 2 to 5 mm) separated from the side portion. The heel side 1 h side which is further than the protruding portion 8 is the arrangement area of the adhesive material 7. The whole protruding portion 8 is situated further on the heel 1 h side than a center C of a toe and heel direction connecting a toe 1 t and the heel 1 h of the golf club head 1. In the case of the golf club head with a volume of about 400 to 460 cc, it is desirable that a distance L (FIG. 3) from the center C to the most toe side of the protruding portion 8 be equal to or larger than 10 mm, for example, about 12 to 30 mm.

The protruding portion 8 has the shape of a metallic wall integrated with the sole portion 4. It is desirable that a height from the sole portion 4 of the highest portion of the wall be 1 to 10 mm, particularly, about 2 to 5 mm. It is desirable that a thickness of the wall of the protruding portion 8 be equal to or less than 3 mm, for example, about 0.5 to 1.5 mm.

As the adhesive material 7, a mixture of a tackifier and a thermoplastic elastomer is preferable. For example, as the tackifier, it is desirable that rosin ester resin, terpene phenol resin, terpene resin, butyl rubber with a low molecular weight, polybutine resin or the like be used, and various elastomers such as thermoplastic resin or polystyrene-based elastomer, polyurethane elastomer or the like be mixed therewith. In order to increase the weight of the golf club head 1, it is desirable that the weight of the adhesive material 7 be equal to or less than 15 g, for example, about 2 to 12 g.

Preferably, the adhesive material 7 is provided by passing an injection nozzle (not shown) through the hosel portion 6 and heating the adhesive material to reduce the viscosity, thereby injecting the same from the injection nozzle to the arrangement area. Since the protruding portion 8 is provided, the adhesive material 7 is arranged in the arrangement area without the adhesive material 7 expanding up to the middle side of the sole portion 4.

It is desirable that a thickness of the sole portion 4 be about 0.5 to 1.2 mm.

The golf club head 1 as configured as above includes the adhesive material 7 therein, and the foreign matter is attached and collected thereto, so an abnormal sound due to the movement of the foreign matter is prevented. Furthermore, the protruding portion 8 is provided on the sole portion 4 to divide the arrangement area of the adhesive material 7, and the adhesive material 7 is arranged only in the arrangement area, so the adhesive material 7 is present only in a limited range of the sole portion 4. For that reason, a decline in primary natural frequency of the sole portion 4 during ball hitting due to the provision of the adhesive material is suppressed, so that the striking sound having no level difference with a golf club head without the adhesive material is generated.

Furthermore, according to research of the inventors, as an occurrence part of the striking sound, the sole portion 4 is a major part. For that reason, by maintaining the primary natural frequency of the sole portion 4 at a high level, a high fresh metallic sound called “snap” peculiar to the metal head is strongly generated.

In the present embodiment, since the protruding portion 8 is separated from the face portion 2, the ball striking speed (the initial speed) increases without affecting the flexure of the face portion 2 during ball hitting. However, although it is not shown, even when the protruding portion 8 is connected to the heel 1 h side of the face portion 2, the ball striking speed increases, while hardly affecting the flexure of the face portion 2 during ball hitting.

In the present embodiment, since the hosel portion 6 has a through hole shape, there is a fear that the foreign matter, which was attached to an inner surface of the hosel portion 6 or a front end portion of the shaft, will fall down from the hosel portion 6 and enters the golf club head 1 when a shaft (not shown) is inserted into the hosel portion 6. In the present embodiment, since the adhesive material 7 is provided on the lower part area of the hosel portion 6, the foreign matter fallen down from the hosel portion 6 falls down on the adhesive material 7 as is and is instantly collected, so an abnormal sound occurrence caused by the foreign matter is securely prevented.

In the present embodiment, the protruding portion 8 has a shape which is bent in the form of an L shape when seen from the plane. However, the protruding portion 8 may be bent in the form of an arc shape which expands toward the middle side of the sole portion 4 like a protruding portion 8A of a golf club head 1A of FIG. 4. In addition, like a protruding portion 8B of a golf club head 1B of FIG. 5, it may have a “<” shape in which a front portion 8 a and a rear portion 8 b intersect each other in the shape of an obtuse angle, and like a protruding portion 8C of a golf club head 1C of FIG. 6, the protruding portion may extend in a straight line shape. Other configurations of the golf club head of FIGS. 4 to 6 are the same as those of the golf club heads of FIGS. 1 to 3, and the identical reference numerals denote the identical portions. Although it is not shown, a plane shape of the protruding portion may be a zigzag shape, a wave line shape or the like.

In the above-mentioned embodiments, although the golf club head was made of metal as a whole, a part, for example, a part of the crown portion or the whole thereof may be formed by materials other than metal such as fiber-reinforced synthetic resin or the like.

First Example

Four golf club heads 1 having the configurations shown in FIGS. 1 to 3 with a volume of 460 cc were manufactured. Main body portions other than the face portion 2 of the golf club head were formed of (Ti-6Al-4V) α-β type titanium alloy which has been made by an investment casting method. The face portion 2 was manufactured by casting a β type titanium alloy and was subjected to a laser welding to the main body portion.

As for thicknesses of each portion of the golf club head, the crown portion was 0.7 mm, the side portion was 0.8 mm, and the sole portion was 0.8 mm. The thicknesses of the face portion were set such that the peripheral edge portion was 2.2 mm, gradually increasing toward the middle portion, and the middle portion was 3.0 mm.

Lengths of the protruding portion 8 were set such that the front portion 8 a was 19 mm and the rear portion 8 b was 50 mm. An intersecting angle of the front portion 8 a and the rear portion 8 b was set to be about 90°. The distance L from the intersecting portion to the center C was set to be 24 mm, the height of the protruding portion 8 was set to be 10 mm in the vicinity of the intersecting portion, and the thickness of the wall was set to be 1 mm.

The injection nozzle was inserted into the hosel portion 6, and 3.4 g of the adhesive material heated at 150° C. (a mixture of the styrene-based elastomer and rosin ester resin or polybutine resin) was injected into the arrangement area. Besides, the adhesive material has an adherence property at ordinary temperatures. However, in a case that the adhesive material is heated, the adhesive material takes on a flow property. A fiber scope was inserted from the hosel portion 6 into the golf club head 1 and observed, then, it was confirmed that the adhesive material was thinly expanded only to the arrangement area of the heel side which is further than the protruding portion 8.

A carbon shaft with a length of 45 inches was installed on the golf club head to manufacture the golf club, and a primary natural frequency of the sole portion of the golf club head was measured. For reference, also regarding the golf club using the golf club head prior to the injection of the adhesive material, the primary natural frequency of the sole portion was measured.

The measurement of the primary natural frequency of the sole portion was performed by attaching an accelerometer to the sole portion with a bonding material, imputing the primary natural frequency when the sole portion is tapped with an impulse hammer into a personal computer (PC) via a data station, and analyzing the same. FFT analytic software for calculating a frequency response function and modal analytic software for calculating a modal parameter is installed in the PC.

Specifically, as each instrument, the following were used.

-   -   data station: DS2000 manufactured by Onosokki Co., Ltd.     -   impulse hammer: 5800SL manufactured by Dytran Co., Ltd.     -   accelerometer: NP3210 manufactured by Onosokki Co., Ltd.     -   FFT analytic software: DS0221 manufactured by Onosokki Co. Ltd.     -   modal analytic software: Visual Modal manufactured by Vibrant         Technology Co. Ltd.

Second Example

Excepts for the fact that the height of the protruding portion was 15 mm and the injection amount of the adhesive material was 6.1 g, the conditions were set to be the same as those of the first example, and a primary natural frequency of the sole portion was measured. For reference, the primary natural frequency of the sole portion was also measured regarding the golf club using the golf club head prior to the adhesive material injection.

First Comparison Example

Except for the fact that a rib was not provided and the adhesive material was injected into the vicinity of the middle of the sole portion, the conditions were set to be the same as those of the first example, and the primary natural frequency of the sole portion was measured. For reference, the primary natural frequency of the sole portion was also measured regarding the golf club using the golf club head prior to the adhesive material injection.

Second Comparison Example

Except for the fact that a rib was not provided and the adhesive material was injected into the vicinity of the middle of the sole portion, the conditions were set to be the same as those of the second example, and the primary natural frequency of the sole portion was measured. For reference, the primary natural frequency of the sole portion was also measured regarding the golf club using the golf club head prior to the adhesive material injection.

TABLE 1 primary natural frequency (Hz) adhesive before after material adhesive adhesive injection material material No amount injection injection difference First 3.4 3153 3131 22 example Second 6.1 3149 3087 62 example First 3.4 3158 3049 110 comparison example second 6.1 3148 2951 197 comparison example

As is apparent from a comparison of the first example with the first comparison example and a comparison of the second example with the second comparison example, as indicated in table 1, in a case where the adhesive material is injected into the heel side, it is confirmed that the a decline in primary natural frequency of the sole portion is reduced as compared to the case of being injected to the vicinity of the middle of the sole portion. Furthermore, there is a strong phase relationship between the primary natural frequency of the sole portion and the striking sound, and the frequency of the striking sound of becomes a low sound as the primary natural frequency of the sole portion is reduced. 

1. A golf club head comprising: a face portion; a sole portion; a side portion; a crown portion defining a hollow portion with the face portion, the sole portion and the side portion; a hosel portion; an adhesive material provided on an inner surface of the hollow portion; and a protruding portion for dividing an arrangement area of the adhesive material, the protruding portion being provided on the sole portion.
 2. The golf club head according to claim 1, wherein the protruding portion is separated from the face portion.
 3. The golf club head according to claim 1, wherein the protruding portion is connected to a heel side of the face portion.
 4. The golf club head according to claim 1, wherein: the hosel portion communicates with an inside and an outside of the golf club head; and the arrangement area is located at a lower side of the hosel portion.
 5. The golf club head according to claim 1, wherein: the protruding portion is located nearer a heel portion in relation to a middle of a toe and heel direction of the sole portion. 